Identification of key factors governing chemistry in groundwater near the water course recharged by reclaimed water at Miyun County, Northern China

Reclaimed water was successfully used to recover the dry Chaobai River in Northern China, but groundwater may be polluted. To ensure groundwater protection, it is therefore critical to identify the governing factors of groundwater chemistry. Samples of reclaimed water, river and groundwater were collected monthly at Chaobai River from January to September in 2010. Fifteen water parameters were analyzed. Two kinds of reclaimed water were different in type (Na-Ca-Mg-Cl-HCO3 or Na-Ca-Cl-HCO3 ) and concentration of nitrogen. The ionic concentration and type in river were similar to reclaimed water. Some shallow wells near the river bed had the same type (Na-Ca-Mg-Cl-HCO3 ) and high concentration as reclaimed water, but others were consistent with the deep wells (Ca-Mg-HCO3 ). Using cluster analysis, the 9 months were divided into two periods (dry and wet seasons), and all samples were grouped into several spatial clusters, indicating different controlling mechanisms. Principal component analysis and conventional ionic plots showed that calcium, magnesium and bicarbonate were controlled by water-rock interaction in all deep and some shallow wells. This included the dissolution of calcite and carbonate weathering. Sodium, potassium, chloride and sulfate in river and some shallow wells recharged by river were governed by evaporation crystallization and mixing of reclaimed water. But groundwater chemistry was not controlled by precipitation. During the infiltration of reclaimed water, cation exchange took place between (sodium, potassium) and (calcium, magnesium). Nitrification and denitrification both happened in most shallow groundwater, but only denitrification in deep groundwater.     

Waste oyster shell as a kind of active filler to treat the combined wastewater at an estuary

Estuaries have been described as one of the most difficult environments on Earth. It is difficult to know how to treat the combined wastewater in tidal rivers at the estuary, where the situation is very different from ordinary fresh water rivers. Waste oyster shell was used as the active filler in this study in a bio-contact oxidation tank to treat the combined wastewater at the Fengtang Tidal River. With a middle-experimental scale of 360 ma/day, the average removal efficiency of COD, BOD, NH3-N, TP and TSS was 80.05%, 85.02%, 86.59%, 50.58% and 85.32%, respectively, in this bio-contact oxidation process. The living microbes in the biofilms on the waste oyster shell in this bio-contact oxidation tank, which were mainly composed of zoogloea, protozoa and micro-metazoa species, revealed that waste oyster shell as the filler was suitable material for combined wastewater degradation. This treatment method using waste oyster shell as active filler was then applied in a mangrove demonstration area for water quality improvement near the experiment area, with a treatment volume of 5 × 10^3 m^3/day. Another project was also successfully applied in a constructed wetland, with a wastewater treatment volume of 1 ×10^3 m^3/day. This technology is therefore feasible and can easily be applied on a larger scale,     

Eutrophication development and its key regulating factors in a water-supply reservoir in North China

Yanghe Reservoir is an important source of drinking water for Qinhuangdao City,North China;however,in recent decades this water source has been eutrophic with recurrent summer cyanobacterial blooms.The trophic grade of the system in summer was mesotrophiceutrophic in 1990 and became hypertrophic in 2011.The nutrient availability is extremely high during the entire year,and the water temperature should be the primary driver of the summer blooms.In May-October of 2010 and 2011,abrupt variations were observed in the Secchi depth(SD) and chlorophyll a(Chl-a),and both the correlated analysis of Chl-a-SD and trophic status indices(TSI) deviation(TSI Chl-a-TSI SD) showed that algal cell density dominated light attenuation.During the algal bloom outbreak,the microcystin concentration was found to vary between 0.35-2.12 μg/L in 2010 and 0.11-1.86 μg/L in 2011.The maximum microcystin content was more than two times the safety limit required for drinking water.Inflow discharges were most concentrated in the summer,with periods of lower residence time and the largest water level fluctuation over the entire year.When a high availability of nutrients promoted a high Chl-a concentration in the whole system,it appeared that the instability caused by the decrease in residence time could not produce effective changes in the cyanobacterial abundance.The results indicated that nutrient enrichment in the aquatic systems of Yanghe Reservoir is the most serious problem and that the status would not been modified effectively by increasing hydrological fluctuations(e.g.,decreasing the residence time).Therefore,decreasing the nutrient concentrations is the only route to improve the water quality of this reservoir.     

铬(Ⅵ)土著还原菌筛选及初步鉴定实验研究

以重铬酸钾为供试物,用固体平板法和还原实验对铬(Ⅵ)土著还原菌进行筛选,用载片培养法、革兰氏染色法、鞭毛染色法、芽孢染色法对还原菌做初步的鉴定,共筛选出16株铬(Ⅵ)土著还原菌,并挑选出还原率相对较高的Z2(35.2%)、Z3(45.2%)、Z4(38.6%)、X8(30.4%)、X10(29.4%)作为铬(Ⅵ)的优势还原菌株。经初步鉴定,土著真菌Z2为黑曲霉(Aspergillusniger),Z3、Z4为镰刀菌属(Fusariumsp.),土著细菌X8、X10为芽孢杆菌(Bacillussp.)。实验的方法和成果将为铬(Ⅵ)污染土壤微生物治理技术的推广应用提供技术支持。     

昆明市主城区三种温室气体的月份和干、湿季的小时变化规律及原因分析

研究了昆明市主城区3种温室气体浓度的最新变化情况,采用2009年、2010年和2011年的月份和小时平均浓度数据,结合昆明市气候特点,对3种温室气体浓度的月份和干、湿季的小时变化规律及原因进行了分析。     

北京道路尘土与土壤植物中重金属形态分析与评价

以北京市航天桥道路尘土、附近道路土壤及绿化植物(大叶黄杨)叶片,玉渊潭公园土壤及绿化植物(大叶黄杨)叶片为研究对象,采用改进的BCR连续提取法、HCl-HNO3-HF-HClO4湿法消解和ICP-MS对Cr、Ni、Cu、Zn、As、Cd和Pb 7种重金属进行形态分析和含量测定。结果表明,样品中重金属Zn的总量最高,Cd的总量最低,细颗粒样品中的重金属含量除Cr和Cu均高于粗颗粒样品。7种重金属中Cr、Ni、Cu、Zn、As和Cd均以残渣态为主,Pb以可还原态和残渣态为主。样品的重金属总量相关性分析表明不同样品的重金属可能均来自交通污染源,总量与形态相关性分析表明总量与残渣态呈显著正相关性。内梅罗污染指数及风险评价法(RAC)结果均表明,道路尘土的重金属污染最为严重。植物对重金属Cd的富集效应最大(富集系数达0.962),路边植物对重金属的富集效应基本均大于公园植物。     

杭州市垃圾填埋甲烷排放估算及控制途径研究

研究和估算固体废弃物填埋处理甲烷的排放,对准确评估未来气候变化以及应对气候变化所带来的影响具有重要的意义。文章在分析了填埋场甲烷产生影响因素的基础上,对2005-2010年杭州市填埋场甲烷排放情况进行了估算,针对性地提出了杭州市填埋场甲烷排放控制的对策建议,为杭州市碳减排工作提供参考意见。     

交通主干道旁室内外苯系物的分析和研究

监测结果表明室外的机动车流量对于室外的苯系物浓度起到较大的贡献作用,并且室外苯系物浓度的变化曲线和机动车流量变化结果呈现出一致性;同时,通过监测还表明室内的三苯浓度变化中,开窗情况下室内的污染物浓度的变化和室外浓度变化是一致,而在关窗情况下室内的三苯浓度变化较为的复杂,这可能是在交通主干道旁和对照点的建筑室内存在三苯污染源。     

关于污染源普查工作中的几点思考

通过对污染源普查工作的探索,在实践中进行验证,现实的思考如何能更好的开展污染普查的工作方法,努力把国情调查工作做的更细致、更全面、更有效,全面实现国情调查的目的.本文根据实践经验对存在问题和解决措施进行归纳总结,并针对性的提出了一些建议和设想,以期为再次的污染源普查工作积累经验.     

哈尼河水源环境风险评估与防范措施的研究

哈尼河是通化市50万人口的重要供水水源地,针对哈尼河水源环境风险进行识别、评估,从而提出风险防范措施,确保水源地水质安全.